General anesthesia is a drug-induced, reversible condition comprised of five behavioral states: unconsciousness, amnesia (loss of memory), analgesia (loss of pain sensation), akinesia (immobility), and hemodynamic stability with control of the stress response. Our work shows that a primary mechanism through which anesthetics create these altered states of arousal is by initiating and maintaining highly structured oscillations. These oscillations impair communication among brain regions. We illustrate this effect by presenting findings from our human studies of general anesthesia using high-density EEG recordings and intracranial recordings. These studies have allowed us to give a detailed characterization of the neurophysiology of loss and recovery of consciousness due to propofol. We show how these dynamics change systematically with different anesthetic classes and with age. We present a neuro-metabolic model of burst suppression, the profound state of brain inactivation seen in deep states of general anesthesia. We use our characterization of burst suppression to implement a closed-loop anesthesia delivery system for control of a medically-induced coma. Finally, we demonstrate that the state of general anesthesia can be rapidly reversed by activating specific brain circuits. The success of our research has depended critically on tight coupling of experiments, signal processing research and mathematical modeling.

Emery N. Brown is the Edward Hood Taplin Professor of Medical Engineering and Computational Neuroscience at MIT; the Warren M. Zapol Professor of Anaesthesia at Harvard Medical School and an anesthesiologist at Massachusetts General Hospital (MGH). Dr. Brown received his B.A (magna cum laude) in Applied Mathematics from Harvard College, his M.A. and Ph.D. in Statistics from Harvard University and his M.D. (magna cum laude) from Harvard Medical School. He completed his internship in internal medicine at the Brigham and Women’s Hospital and his residency in anesthesiology at MGH.

His experimental research has characterized the neurophysiological mechanisms of how anesthesia works. His statistics research develops point process, state-space and spectral analysis methods to characterize how the brain represents and transmits information.

Dr. Brown served on the NIH BRAIN Initiative Working Group and is the recipient of an NIH Pioneer Award, the National Institute of Statistical Sciences Sacks Award, the American Society of Anesthesiologists Excellence in Research Award and a Guggenheim Fellowship in Applied Mathematics. He is a Fellow of the American Statistical Association, Institute for Mathematical Statistics, IEEE, American Association for the Advancement of Science, American Academy of Arts and Sciences and National Academy of Inventors. Dr. Brown is a member of the National Academy of Medicine, National Academy of Sciences and National Academy of Engineering.

About the Glassman Lecture:

The Glassman Lecture is held in honor of the late Harold N. Glassman who left a generous bequest to the MBL which resulted in the establishment of the Harold N. Glassman fund, the income from which is used to support an annual Friday Evening Lecture on an important topic in biological research.